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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /security/nss/lib/freebl/mpi/utils/fact.c
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'security/nss/lib/freebl/mpi/utils/fact.c')
-rw-r--r--security/nss/lib/freebl/mpi/utils/fact.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/mpi/utils/fact.c b/security/nss/lib/freebl/mpi/utils/fact.c
new file mode 100644
index 000000000..da8e61a32
--- /dev/null
+++ b/security/nss/lib/freebl/mpi/utils/fact.c
@@ -0,0 +1,84 @@
+/*
+ * fact.c
+ *
+ * Compute factorial of input integer
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mpi.h"
+
+mp_err mp_fact(mp_int *a, mp_int *b);
+
+int
+main(int argc, char *argv[])
+{
+ mp_int a;
+ mp_err res;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s <number>\n", argv[0]);
+ return 1;
+ }
+
+ mp_init(&a);
+ mp_read_radix(&a, argv[1], 10);
+
+ if ((res = mp_fact(&a, &a)) != MP_OKAY) {
+ fprintf(stderr, "%s: error: %s\n", argv[0],
+ mp_strerror(res));
+ mp_clear(&a);
+ return 1;
+ }
+
+ {
+ char *buf;
+ int len;
+
+ len = mp_radix_size(&a, 10);
+ buf = malloc(len);
+ mp_todecimal(&a, buf);
+
+ puts(buf);
+
+ free(buf);
+ }
+
+ mp_clear(&a);
+ return 0;
+}
+
+mp_err
+mp_fact(mp_int *a, mp_int *b)
+{
+ mp_int ix, s;
+ mp_err res = MP_OKAY;
+
+ if (mp_cmp_z(a) < 0)
+ return MP_UNDEF;
+
+ mp_init(&s);
+ mp_add_d(&s, 1, &s); /* s = 1 */
+ mp_init(&ix);
+ mp_add_d(&ix, 1, &ix); /* ix = 1 */
+
+ for (/* */; mp_cmp(&ix, a) <= 0; mp_add_d(&ix, 1, &ix)) {
+ if ((res = mp_mul(&s, &ix, &s)) != MP_OKAY)
+ break;
+ }
+
+ mp_clear(&ix);
+
+ /* Copy out results if we got them */
+ if (res == MP_OKAY)
+ mp_copy(&s, b);
+
+ mp_clear(&s);
+
+ return res;
+}